Search

Computational Fluid Dynamics (CFD) simulations are increasingly employed in the development of latent thermal energy storage units. Yet there are often strong deviations between the experiments and numerical results. To unveil the sources of the deviations for the CFD simulation of a vertical shell-and-tube latent thermal energy storage unit, a basic analysis of different uncertainties is undertaken in this paper. Consequently, the effect of a variation of 10 material properties, six initial and boundary conditions, as well as a displacement of the temperature measuring points in the simulation, are examined. The results depict that the influence of the substance data depend on the output variable under consideration. Beside material properties, which have almost no influence, there are some properties that influence the power and the global liquid phase fraction over time, and a third group, which also has an influence on the mean power. Partly in contrast to results found in literature, the highest influence on the mean power occurs for the heat losses (which are varied in an on/off manner), the density, and the melting enthalpy (both varied by &plusmn, 10%).

International audience; This work considers the shape optimization of a crossflow plate heat exchanger air/water. The two objectives are to maximize the effectiveness while minimizing the total pressure drop. The shape variation concerns a trapezoidal rib mounted on the hot channels plates. A multiscale approach is presented, coupling CFD simulations and a NTU method. The optimization method is based on a genetic algorithm and kriging metamodels with adaptive sampling. Infill criteria are the maximum mean square error (MMSE) and multipoints expected improvement (q-EI). A clustering of the Pareto front individuals highlights a finite number of optimal shapes.